Currently static atoms are stored on the heap, but their char buffers are
stored in read-only static memory.
This patch changes the representation of nsStaticAtom (thus making it a
non-trivial subclass of nsAtom). Instead of a pointer to the string, it now has
an mStringOffset field which is a 32-bit offset to the string. (This requires
placement of the string and the atom within the same object so that the offset
is known to be small. The docs and macros in nsStaticAtom.h handle that.)
Static and dynamic atoms now store their chars in different ways: nsStaticAtom
stores them inline, nsDynamicAtom has a pointer to separate storage. So
`mString` and GetStringBuffer() move from nsAtom to nsDynamicAtom.
The change to static atoms means they can be made constexpr and stored in
read-only memory instead of on the heap. On 64-bit this reduces the per-process
overhead by 16 bytes; on 32-bit the saving is 12 bytes. (Further reductions
will be possible in follow-up patches.)
The increased use of constexpr required multiple workarounds for MSVC.
- Multiple uses of MOZ_{PUSH,POP}_DISABLE_INTEGRAL_CONSTANT_OVERFLOW_WARNING to
disable warnings about (well-defined!) overflow of unsigned integer
arithmetic.
- The use of -Zc:externConstexpr on all files defining static atoms, to make
MSVC follow the C++ standard(!) and let constexpr variables have external
linkage.
- The use of -constexpr:steps300000 to increase the number of operations
allowed in a constexpr value, in order to handle gGkAtoms, which requires
hashing ~2,500 atom strings.
The patch also changes how HTML5 atoms are handled. They are now treated as
dynamic atoms, i.e. we have "dynamic normal" atoms and "dynamic HTML5 atoms",
and "dynamic atoms" covers both cases, and both are represented via
nsDynamicAtom. The main difference between the two kinds is that dynamic HTML5
atoms still aren't allowed to be used in various operations, most notably
AddRef()/Release(). All this also required moving nsDynamicAtom into the header
file.
There is a slight performance cost to all these changes: now that nsStaticAtom
and nsDynamicAtom store their chars in different ways, a conditional branch is
required in the following functions: Equals(), GetUTF16String(),
WeakAtom::as_slice().
Finally, in about:memory the "explicit/atoms/static/atom-objects" value is no
longer needed, because that memory is static instead of heap-allocated.
MozReview-Commit-ID: 4AxPv05ngZy
MOZ_LOG=modules:4,raw now outputs the log without prefixes with the thread name
and date and stuff, just the exact string that was specified.
MozReview-Commit-ID: HACT5EM4BFm
--HG--
extra : rebase_source : 93590ee405f013791ad63565be6e6d83cad3567f
extra : source : d79d7130b28275c8eb2a475bdc685a345b070888
clang-tidy is complaining about an extra else in
NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION. Not hurting anything, but
could be cleaned up anyways.
MozReview-Commit-ID: 36Lkdhs3fyN
--HG--
extra : rebase_source : 74088c9c2668f43d55133be240d4591880b60dab
The old output had a single value: "atoms-table". The new output looks like
this:
> 649,904 B (00.39%) -- atoms
> ├──350,256 B (00.21%) -- dynamic
> │ ├──235,056 B (00.14%) ── unshared-buffers
> │ └──115,200 B (00.07%) ── atom-objects
> ├──212,992 B (00.13%) ── table
> └───86,656 B (00.05%) ── static/atom-objects
MozReview-Commit-ID: 924vUmxHAlh
--HG--
extra : rebase_source : 6c977546a69eeee62ebc87e335982e8278217484
Various atom-related things have improved recently.
- The main atom table is now threadsafe (bug 1275755) and so can be accessed on
any thread. It has also been split into pieces (bug 1440824), which greatly
reduces lock contention.
- A cache has been added to the HTML5 parser (bug 1352874) that removes the
need for most of the full table lookups.
As a result, there is no point having a separate static atom table. This patch
removes it.
MozReview-Commit-ID: 8ou1BrnPAwd
--HG--
extra : rebase_source : 0c6ab073b1a20b703705582d28731a68456741e1
This also changes a few MOZ_LOG() messages to use the error name
instead of the raw numerical nsresult value.
MozReview-Commit-ID: Jcngd0S9j2z
--HG--
extra : rebase_source : f6e974569d8845211e0b25dabef2c41dda2ca1b6
nsSetDllDirectory.h consists of just one function definition, SanitizeEnvironmentVariables, which is now only called from nsWindowsMain.cpp. nsSetDllDirectory.h used to define its namesake NS_SetDllDirectory, but the function was removed in bug 699247.
Also remove some #includes that are no longer necessary.
MozReview-Commit-ID: E8OsXycdfO8
--HG--
extra : rebase_source : d9e63a50a782ab1fb0fde24646a777b882860fb9
extra : histedit_source : 63c41846db2bb6a1def03c343e6f336373f1fba6
This adds some assertions to make the intended usage of LogModuleManager::Init
more clear.
--HG--
extra : rebase_source : c61e1736cedfbeaa96951ba40cdc954bbc0094d5
The change to RootAccessible.cpp fixes an obvious bug introduced in bug 741707.
The visibility changes in gfx/thebes are because NS_DECL_ISUPPORTS has a
trailing "public:" that those classes were relying on to have public
constructors.
MozReview-Commit-ID: IeB8KIJCGhU
This macro is identical to NS_INTERFACE_MAP_END and encourages the
reader to think that there's something extra-special threadsafe about QI
implementations that use the macro, when in reality there's nothing of
the sort.
This patch adds a new environment variable XPCOM_MEM_LOG_JS_STACK that
changes XPCOM leakchecking to record a JS stack for all objects, in
addition to a C++ stack. This is useful when a C++ object is being
leaked due to JS. The JS stack will be printed if the object leaks, if
it is used in combination with XPCOM_MEM_BLOAT_LOG=1 and
XPCOM_MEM_LOG_CLASSES=nsFoo, if nsFoo is the class of interest.
This patch moves a few XPConnect functions for recording the stack
into xpcpublic.h so they can be called from nsTraceRefcnt.cpp.
MozReview-Commit-ID: FX2QVCSXz4f
--HG--
extra : rebase_source : 5bd4e341072f4cf7d3be774b63d2107479fe9985
Honza Bambas
Henri Sivonen
Masatoshi Kimura
Nicholas Nethercote
Steve Fink
Petr Sumbera
Paul Adenot
Kyle Machulis
Nathan Froyd
Olli Pettay
Tiberius Oros
Csoregi Natalia
Eugen Sawin
Francois Marier
Sylvestre Ledru
Chris Peterson
Jason Orendorff
Kirk Steuber
Eric Rahm
Boris Zbarsky
David Major
Andrew McCreight
Alex Gaynor